The rapid growth of data traffic driven by mobile devices poses challenges on capacity of wireless networks. Multi-input-multi-output (MIMO) and multiuser MIMO (MU-MIMO) are key technologies introduced in the 3GPP LTE and LTE-advanced systems to improve spectral efficiency. In current MIMO systems, an evolved Node B (eNB) is usually equipped with a linear array with antenna elements placed in a horizontal line, and the eNB exploits spatial diversity in the azimuth (horizontal) domain. In contrast, deploying antennas vertically allows eNBs to utilize diversity in elevation domain by, for example, elevation beamforming, achieving up to 30% gain in system capacity.